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Java and security expert with over 10 years of experience with the language and with the practical application of cryptographic protocols - including the design of protocols within international standardization bodies. Creator of a heavily used common criteria certified product. Over 30 years of experience with computers. Likes kids, cats, reading, movies and several sports.


Sep
6
accepted Bit padding instead of PKCS#5 padding
Sep
6
comment Bit padding instead of PKCS#5 padding
Yeah, that idea came to me too. I guess that makes the rest moot. I don't see any implementation switching to partial byte encryption soon.
Sep
6
asked Bit padding instead of PKCS#5 padding
Sep
4
comment Would xoring 2 independant AES CTRs to produce p-rand introduce vulnerabilities?
That pseudo OTP sounds like a stream cipher to me, and when you use CTR with AES-256 (correctly) then you've already met the criteria (given that AES-256 isn't broken in the mean time, but that goes for any algorithm).
Sep
4
comment Is RSA encryption the same as signature generation?
When downvoting, please explain why the question is not good or indicate how it can be improved.
Sep
4
comment Is this correct way to generate stream cipher using AES CTR mode?
@CodesInChaos Right you are. A good explanation can be found on the Keccak website. The paper in the question discusses general techniques, I guess the choice of mode/key/iv use should be part of a protocol design.
Sep
4
revised Is this correct way to generate stream cipher using AES CTR mode?
added 29 characters in body
Sep
4
revised Is this correct way to generate stream cipher using AES CTR mode?
added 157 characters in body
Sep
4
answered Is this correct way to generate stream cipher using AES CTR mode?
Sep
4
revised Is this correct way to generate stream cipher using AES CTR mode?
added 54 characters in body
Sep
4
comment ECIES: Purpose of MAC?
+1 of course. Maybe add padding oracle attacks in the mix - they also let you loose confidentiality and are thwarted by validating the MAC before unpadding.
Sep
3
comment What is the exact purpose of length padding in Merkle–Damgård hash functions?
Voted down as bit padding - which is usually performed for hash functions - is fully reversible. You don't need to encode the length to achieve the same thing as you describe (as long as you always pad).
Sep
3
comment Advantages of using intermediate hash over full hash in digital signature application
@DrLecter OK, so that's one reason why this could have advantages, thanks! A hash list or tree would make more sense if you control the protocol of course. Not applicable at all for my situation, but it may be in a rationale in the general sense.
Sep
3
revised Advantages of using intermediate hash over full hash in digital signature application
rewrote to different term; partial hash could also mean part of the final hash value
Sep
3
comment Advantages of using intermediate hash over full hash in digital signature application
@DrLecter It is provided by the terminal as well. In that sense there is no difference - all data is present in the terminal (to sign a document, you need the document, you're not first going to split it and distribute).
Sep
3
revised Entropy of the key
cleared things up according to comments
Sep
3
comment Advantages of using intermediate hash over full hash in digital signature application
Personally I really dislike partial hashes; I'll ask the creators of the protocol as well if they can give substantial reasons to apply them.
Sep
3
asked Advantages of using intermediate hash over full hash in digital signature application
Sep
3
reviewed Close How Proof all Subgroup point of prime order elliptic curve have prime order [#G=#E]?
Sep
2
answered How is the following different than RSA Signing of a document?